POS0780 PSEUDOGOUT OF THE TEMPOROMANDIBULAR JOINT: A CASE REPORT
Authors: B. Maranini, S. Mandrioli, M. Galiè, M. Govoni
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Deposition of calcium pyrophosphate dihydrate crystals occurs in crystalline arthropathies, such as gout and chondrocalcinosis. Occasionally, crystal deposits may affect the temporomandibular joint (TMJ), especially involving the articular cartilage and fibrocartilage, causing pain and jaw claudication, mimicking giant cell arteritis (GCA). Ultrasound (US) images reveal spotted hyperechoic signals in the articular disk and sometimes a marked destruction of the condyle with erosive changes. <h3>Objectives</h3> To highlight and discuss the potential role of TMJ US in guiding differential diagnosis of orofacial pain syndrome (frontal headache and jaw claudication), arousing the suspicion of GCA. <h3>Methods</h3> Case-report describing an old patient presenting with severe headache and jaw claudication with particular reference to the role of TMJ US in differential diagnosis of an initially suspected GCA. <h3>Results</h3> An 85-year-old woman presented to the Emergency Department with a 2-days history of progressively worsening frontal headache and jaw claudication. She reported no visual loss or polymyalgia rheumatica symptoms. Right temporal artery tenderness was appreciated on clinical examination, without reduced temporal artery pulse. No axillary, brachial, or carotid bruits were appreciated. Neurologic examination was normal; brain computed tomography (CT) revealed no intracerebral hemorrhage or intraparenchymal lesions. Her erythrocyte sedimentation rate was 67 mm per hour, and C-reactive protein level 3.30 mg per deciliter. Temporal artery US revealed no abnormalities (absence of halo sign or arterial stenosis). Since patient complained of chewing pain and given that temporomandibular disorders may be misdiagnosed as GCA, TMJ US was performed revealing the presence of extensive calcifications around the right temporomandibular head and in the meniscus (Figure 1, Panel A). Brain CT images were then carefully reviewed: in the right TMJ massive calcifications surrounding the right temporomandibular head were appreciable (Figure 1, Panel B). Moreover, coronal CT scan of the atlantoaxial region showed calcifications of the alar ligaments, particularly evident on the superior-left side (Figure 1, Panel C). High dose glucocorticoid regimen was then started (Methylprednisolone 40 mg once daily). The patient's pain rapidly improved, steroid was rapidly tapered until withdrawal, with a complete resolution of symptoms within few weeks. <h3>Conclusion</h3> Crowned dens syndrome is characterized by recurrent neck pain related to radiodense deposits of hydroxyapatite or calcium pyrophosphate dihydrate in ligaments around the odontoid process, which create the appearance of a crown or halo surrounding the odontoid process on radiographic imaging. Evidence of inflammation (e.g., fever or elevated levels of C-reactive protein) is usually observed. A short course of steroids, followed by administration of nonsteroidal anti-inflammatory medication, usually completely alleviates symptoms. Rarely, temporal arteritis headache may mimic TMJ irradiation pain, or present as jaw claudication. In this case, temporal arteries and TMJ US can enable to discern a halo sign, as a hallmark of giant cell arteritis, from suspicious signs of TMJ disorder. Rapid diagnosis can prevent misdiagnosis, invasive and unnecessary investigations (temporal artery biopsy) and inappropriate treatment (long term steroid regimen, leading to cardiovascular risk and increased bone loss). <h3>References</h3> [1]Matsumura Y, Nomura J, Nakanishi K, Yanase S, Kato H, Tagawa T. Synovial chondromatosis of the temporomandibular joint with calcium pyrophosphate dihydrate crystal deposition disease (Pseudogout). <i>Dentomaxillofac Radiol.</i> (2012) 41:703–7. doi: 10.1259/dmfr/24183821 [2]Austin D, O'Donnell F, Attanasio R. Temporal arteritis mimics TMJ/myofascial pain syndrome. Ohio Dent J. 1992;66(1):44-7. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.